The current-voltage characteristics with acceptor segregation at grain boundaries have been investigated in H-2-sintered SrTiO3. Al-added SrTiO3 was sintered in H-2 and then annealed in air for selective oxidation of grain boundaries. The samples showed nonlinear current-voltage characteristics, and both the breakdown voltage and nonlinearity coefficient increased with Al concentration. An energy dispersive spectroscopy analysis revealed that Al ions were segregated at the grain boundary, suggesting the formation of Schottky barriers at the boundary. The present results thus point toward the possibility of modifying the grain boundary composition in SrTiO3 as well as fabricating effective switching devices by H-2 sintering. (c) 2006 American Institute of Physics.